My dad was in the RAF. We used to sing this song but the only lines I remember are:
Three - three the sergeant(s)
Two - two apprentice's wings, dressed in black and green-oh
One is on and all along (alone) and ever more shall be so.

One of the lines has the phrase "for a packet of Player's" which, obviously refers to the cost of cigarettes in the day.

Wish I could remember the whole thing. (Wish Dad was still here.)